Generally, a battery is assembled by interposing a separator between a positive electrode and a negative electrode. In this case, the separator placed between both electrodes of the battery is a member that prevents the positive electrode and the negative electrode from being internally shorted due to a direct contact therewith, and is not only an ion path within the battery but also plays an important role in improving safety of the battery.
A zinc-air battery includes a positive electrode, a separator, an electrolyte, and a negative electrode. First, the positive electrode includes a carbon layer, a positive electrode collector having a shape of metal mesh formed in the carbon layer, and a Teflon layer formed at an upper portion of the carbon layer.
Also, the separator is placed at a lower portion of the carbon layer, and a negative electrode collector of the negative electrode is formed while being spaced a predetermined distance apart from the separator.
The electrolyte is formed to have a shape of a slurry in which zinc (Zn), potassium hydroxide (KOH) and water (H2O) are mixed altogether, and is accommodated between the separator and the negative electrode collector. In this case, the electrolyte passes through the separator and submerges a part of the carbon layer, thereby forming a vapor liquid interface.
The zinc-air battery having the above structure operates due to movement of electrons generated when Zn contained in the electrolyte reacts with oxygen in the air and is changed into a zinc oxide.
In the above-described zinc-air battery according to the related art, the electrolyte submerges a part of the carbon layer through a plurality of through-holes of the separator. In this case, potassium hydroxide contained in the electrolyte reacts with oxygen in the air and is precipitated from a reaction structure. Thus, the carbon layer is destroyed, and thus performance of the zinc-air battery is degraded.
In addition, when the zinc-air battery is charged, oxygen is moved to the positive electrode. The oxygen moved to the positive electrode and potassium hydroxide react with each other and are precipitated from a reaction structure, and thus it is difficult to use the zinc-air battery as a secondary battery.